title: Association between maternal iron supplementation during pregnancy and risk of celiac disease in children.
abstract: OBJECTIVE
  The aim of our study was to determine whether the use of iron supplements during pregnancy affects the risk for celiac disease in children.
  
  
  METHODS
  We assessed data from the prospective Norwegian Mother and Child cohort study, in which individuals with celiac disease were identified by answers on questionnaires and linkage to the Norwegian Patient Register. Complete data were available for 78,846 children (mean age 5.9 years, range 2-12 years); 314 children were identified with celiac disease. Questionnaires were given to pregnant women to collect information on use of iron-containing supplements, diet, anemia, and levels of hemoglobin.
  
  
  RESULTS
  Celiac disease was diagnosed in 4.65 of 1000 children whose mothers took iron supplements while they were pregnant, compared with 3.15 of 1000 children whose mothers did not. After adjusting for children's age, sex, and age of gluten introduction, and the presence of celiac disease in mothers, iron supplementation during pregnancy remained significantly associated with celiac disease in children (odds ratio [OR], 1.33; 95% confidence interval [CI], 1.05-1.68; P = .019). However, celiac disease was not associated with the mothers' intake of iron from foods (adjusted OR, 1.00; 95% CI, 0.97-1.03). Anemia before or during the early stages of pregnancy was not significantly associated with the risk of celiac disease in children (adjusted OR, 1.24; 95% CI, 0.84-2.00; P = .24). The use of iron supplements during pregnancy remained significantly associated with celiac disease in children after adjusting for children who were given iron supplements before 18 months of age, which itself was associated with celiac disease.
  
  
  CONCLUSIONS
  In a prospective Norwegian Mother and Child cohort study, we found an increased risk of celiac disease in children whose mothers used iron supplements during pregnancy; this association does not appear to arise from maternal anemia.
authors.affiliation: Norwegian Institute of Public Health, Oslo, Norway; Østfold Hospital Trust, Fredrikstad, Norway. Electronic address: ketil.stordal@fhi.no.
authors.forename: Ketil
authors.initials: K
authors.lastname: Størdal
authors.affiliation: Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Margaretha
authors.initials: M
authors.lastname: Haugen
authors.affiliation: Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Anne Lise
authors.initials: AL
authors.lastname: Brantsæter
authors.affiliation: Endoscopy Unit, Department of Transplantation Medicine, Oslo University Hospital, Oslo, Norway; Centre for Immune Regulation, University of Oslo, Oslo, Norway.
authors.forename: Knut E A
authors.initials: KE
authors.lastname: Lundin
authors.affiliation: Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Lars C
authors.initials: LC
authors.lastname: Stene
mesh_terms: D000740:Anemia / Q000517:prevention & control*; D002446:Celiac Disease / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004032:Diet / Q000009:adverse effects* / Q000379:methods*; D005260:Female; D006801:Humans; D007501:Iron / Q000009:adverse effects* / Q000627:therapeutic use*; D008297:Male; D009664:Norway / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000517:prevention & control*; D015995:Prevalence; D011446:Prospective Studies; D018570:Risk Assessment; D011795:Surveys and Questionnaires
chemical_list: D007501:Iron
keywords: Enteropathy; Genetic Factor; Immune Development; MoBa Study